The present invention relates to a method and apparatus for treating filter material which is utilized in smokers' products, especially for treating continuous filter rods and/or sections of filter rods which can be utilized in the manufacture of filter cigarettes, cigars or cigarillos. More particularly, the invention relates to treatment of rod-like filters wherein a tubular wrapper of non-conductive material surrounds one or more rod-like fillers consisting of non-conductive material. For example, the wrapper may consist of paper or imitation cork and the filler may consist of paper or acetate fibers. The term "non-conductive" is intended to denote dielectrics as well as materials which are poor conductors of electricity, i.e., materials which tend to retain electrostatic charges.
Filter rods which are used in the mass-production of filter cigarettes or analogous rod-shaped smokers' products are normally produced in machines wherein a tow of fibrous filter material is conditioned with a plasticizer and is thereupon wrapped into a web of paper or the like. The thus obtained rod is severed at regular intervals to yield a succession of filter rod sections of desired length which are transported to storage or directly or indirectly to one or more consuming machines. The components of the filter rod, the filter rod and its sections are in continuous motion; as a rule, the movement is interrupted only when the filter rod sections enter a charger or tray, the magazine of a machine which assembles filter rod sections with plain cigarettes or the like, or the magazine of a pneumatic sender which propels filter rod sections into the magazines of discrete machines for the making of filter tipped smokers' products.
When the material of the filler moves relative to its conveying means, when the material of the wrapper moves relative to its conveying means and/or relative to the material of the filler, when the filaments of the filler move relative to each other, when the filter rod moves relative to its supporting and/or advancing means, and/or when the filter rod sections move relative to their supporting and advancing means, such materials accumulate substantial electrostatic charges. These charges are often highly undesirable because they prevent reproducible transport of successive filter rod sections by opposing the movement of sections along a predetermined path or by causing the sections to move along a path other than the desired path. For example, electrostatic charging of filter rod sections could cause undesirable shifting of sections in the interior of a charger or tray which consists of a synthetic plastic material. The elimination of such charges is not possible by simple grounding of the machine or those machine components which contact the filter material.